The present invention relates to a mechanical press and, more particularly, to a motor driven barring or inching system for incrementally driving the slide toward or away from the bed during tooling setup.
The typical mechanical press comprises a frame having a crown and bed mounted at opposite ends and a slide supported within the frame for motion toward and away from the bed. The bed is mounted to a platform on the floor of the shop. The crown portion is mounted within one or more uprights to create a vertically spaced separation between the crown and bed. The crown contains the drive assembly for the slide, which generally comprises a crankshaft having a plurality of eccentrics thereon and connecting rods connected to the eccentrics of the crankshaft at their upper ends and to the slide at their lower ends. The slide is mounted within the uprights for vertical reciprocating motion and is adapted to have the upper half of the die set mounted to it with the other half mounted to the bolster, which is connected to the bed.
A flywheel and clutch assembly are usually mounted at one end of the crankshaft. The flywheel is connected by a belt to the output pulley of a main drive motor so that when the motor is energized, the massive flywheel continuously rotates. When the clutch is energized, the rotary motion of the flywheel is transmitted to the crankshaft which causes the connecting rods to undergo rotary-oscillatory motion. This motion is transmitted to the slide assembly by means of a wrist pin, for example, so that the rotary-oscillatory motion is converted to straight reciprocating motion. The connecting rods are connected directly to the slide or connected by means of pistons which in turn are slidably received within cylinders connected to the crown.
During tooling setup, it is desirable to set the slide to a particular stroke position. The prior art includes at least two methods for accomplishing this task. The first method is to insert a lever, such as a long metal bar, into bores within the flywheel and lift or pull down the bar, to manually rotate the flywheel thereby causing the slide to move up or down. This method is awkward and inefficient. Two operators are required to set the slide to the desired stroke position. One operator is required to lift the bar and turn the flywheel while the other operator watches and informs the first operator when the slide reaches the desired stroke position. The view of the motion of the slide for the first operator is limited, making it difficult for the operator to determine the position of the slide.
A second method for adjusting the slide to a particular stroke position is to intermittently engage the clutch, while the flywheel is spinning, thereby incrementally moving the slide along until it reaches the desired stroke position. This method is problematic because of the difficulty in moving the slide by small increments and because the frequent engagement and disengagement of the clutch causes the associated clutch and brake pads to overheat, wear excessively, and warp.